For what's believed to be the first time, a San Francisco district attorney has filed a homicide charge against a police officer for shooting a citizen while in the line of duty. And while the result may still be an involuntary manslaughter conviction, it marks a major shift at a time when the country is reckoning with the role of police.

SF District Attorney Chesa Boudin announced Monday that he has filed a manslaughter charge against former rookie SFPD Officer Christopher Samayoa for the December 1, 2017 shooting of 42-year-old Keita O’Neil. O'Neil was believed to have carjacked a state lottery worker's minivan and was running from police, unarmed, after crashing the van into a fence in the Bayview. That was when Samayoa fatally shot O'Neil in the head through the passenger window of a squad car, as O'Neil was running past the vehicle.

Samayoa was a recent graduate of the police academy and was still in field training when the shooting took place. The SFPD fired Samayoa in March 2018.

As the Chronicle reports, the new charges against Samayoa mark "the first time in modern history that the city's top prosecutor has charged a police officer with homicide in a use-of-force case." And the Examiner suggests that this is believed to be the first time, full stop.

In a press conference outside City Hall, Boudin called the incident the result of an officer's "terrible, tragic and unlawful decision to pull and shoot his gun."

"In San Francisco there has been a long history of officer-involved shootings leading to no accountability whatsoever, further cementing the idea that police are above the law,” Boudin said, per the Examiner. "That stops today."

Boudin said Monday that a murder charge is still not off the table, but for now it would be up to a jury to decide between involuntary or voluntary manslaughter — the difference being whether Samayoa acted with "criminal negligence," or whether he acted in "unreasonable self-defense."

Body-worn camera footage from Samayoa, seen below, shows the split-second in which the patrol car pulled up to the scene and Samayoa raised his gun to fire through the passenger window as O'Neil ran past.

170973802-OIS-BWC from San Francisco Police on Vimeo.

Samayoa was also charged with assault with a firearm, reckless discharge of a firearm, and unlawful assault by a police officer. The charges come just as the statute of limitations on the crime was about to expire on December 1, 2020.

And, as Boudin said today, these charges come in part as a result of the Independent Investigations Bureau that former DA George Gascon established in 2016, but which Boudin said had been "extremely unproductive" thus far. He said he was in the process of "rebuilding" the unit, and it would also be in charge of overseeing the case against two Alameda County Sheriff's deputies involved in the beating of a suspect in a Mission District alley in 2015. Boudin recently dismissed charges against the deputies, pledging to refile new charges in the near future.